The present invention relates to an arrangement for the relative angle of rotation adjustment of a camshaft of an internal-combustion engine with respect to a driving wheel.
An arrangement of the type mentioned above is known from German Patent Document DE 196 23 818 A1. In a fifth embodiment (see Figures 15 to 18), sealing elements are arranged on faces of rotor blades of a camshaft adjusting device. These sealing elements, which are not indicated in detail, have the purpose of preventing hydraulic oil used for adjusting the rotor with respect to the stator from flowing from the pressure chambers acted upon by hydraulic oil by way of the face of the rotor blades to the adjusting chambers which are momentarily unpressurized.
A vane cell camshaft adjuster is also known from German Patent Document DE 197 45 908 A1. In this case, recesses are provided on faces of the rotor blades, in which recesses roller-shaped rolling bodies are received. These rolling bodies are used for reducing the frictional forces between the driving wheel and the impeller (rotor). The rolling bodies are supported, on one side, directly in the recess and, on the other side, directly at the interior wall of the driving wheel.
In an adjusting unit illustrated in German Patent Document DE 199 22 194 A1, recesses are also provided on the faces of the rotor blades. Rectangular sealing bodies are arranged in these recesses. During operation of the internal-combustion engine, hydraulic oil is delivered into the recesses by way of a leakage gap constructed between the rotor blades and the stator (driving wheel). As a result, the rectangular sealing bodies are pressed, by means of a first lateral surface, against the stator and, by means of a second lateral surface, against the interior flank of the sealing groove (see, for example, Figure 7).
It is an object of the invention to improve an arrangement of this type for the relative angle of rotation adjustment of a camshaft with respect to its driving wheel such that a simple sealing-off of the two pressure spaces of the camshaft adjusting device, which are separated from the rotor blade, takes place in a way which is improved with respect to the prior art.
According to the invention, this object is achieved.
The rollers provided as sealing bodies in the recesses of the rotor blades provide a line contact at the stator (driving wheel) as well as on the interior surface of the sealing groove. This line contact ensures a greater contact pressure force, and thus a more reliable sealing-off of the two pressure spaces separated from the rotor blades, in comparison to a surface contact (see DE 199 22 194 A1). Furthermore, because of the two line contacts of the rollers used, the friction is significantly less in contrast to the rectangular sealing elements.